import type { CustomerType } from './types';

export type HydrogenDrillLevel = 'overview' | 'station' | 'customer';

export interface HydrogenDrillContext {
  level: HydrogenDrillLevel;
  year?: number;
  stationId?: number;
  stationName?: string;
  customerName?: string;
  vehicleScope: CustomerType;
  startDate?: string;
  endDate?: string;
  selectedDate?: string;
  orderPage?: number;
}

interface LocationParts {
  pathname: string;
  search: string;
  hash: string;
}

const DATE_PATTERN = /^\d{4}-\d{2}-\d{2}$/;

function validDate(value: string | null): string | undefined {
  if (!value || !DATE_PATTERN.test(value)) return undefined;
  const timestamp = Date.parse(`${value}T00:00:00+08:00`);
  return Number.isFinite(timestamp) ? value : undefined;
}

function positiveInteger(value: string | null): number | undefined {
  if (!value || !/^\d+$/.test(value)) return undefined;
  const parsed = Number(value);
  return Number.isSafeInteger(parsed) && parsed > 0 ? parsed : undefined;
}

function stationId(value: string | null): number | undefined {
  if (!value || !/^\d+$/.test(value)) return undefined;
  const parsed = Number(value);
  return Number.isSafeInteger(parsed) && parsed >= 0 ? parsed : undefined;
}

export function parseHydrogenDrillContext(search: string): HydrogenDrillContext {
  const params = new URLSearchParams(search);
  const requestedLevel = params.get('hydrogenLevel');
  const parsedStationId = stationId(params.get('hydrogenStation'));
  const parsedStationName = params.get('hydrogenStationName')?.trim() || undefined;
  const rawCustomerName = params.get('hydrogenCustomer')?.trim();
  const customerName = rawCustomerName && rawCustomerName.length <= 128
    ? rawCustomerName
    : undefined;
  const context: HydrogenDrillContext = {
    level: requestedLevel === 'station' && parsedStationId !== undefined
      ? 'station'
      : requestedLevel === 'customer' && customerName
        ? 'customer'
        : 'overview',
    vehicleScope: params.get('hydrogenScope') === 'external' ? 'external' : 'lingniu',
  };

  const year = positiveInteger(params.get('hydrogenYear'));
  if (year && year >= 2000 && year <= 2100) context.year = year;
  if (context.level === 'station') {
    context.stationId = parsedStationId;
    if (parsedStationName) context.stationName = parsedStationName;
  }
  if (context.level === 'customer') context.customerName = customerName;
  const startDate = validDate(params.get('hydrogenStart'));
  const endDate = validDate(params.get('hydrogenEnd'));
  const selectedDate = validDate(params.get('hydrogenDate'));
  if (startDate) context.startDate = startDate;
  if (endDate) context.endDate = endDate;
  const rangeStart = startDate && endDate ? (startDate <= endDate ? startDate : endDate) : undefined;
  const rangeEnd = startDate && endDate ? (startDate <= endDate ? endDate : startDate) : undefined;
  if (selectedDate && (!rangeStart || !rangeEnd || (selectedDate >= rangeStart && selectedDate <= rangeEnd))) {
    context.selectedDate = selectedDate;
    const orderPage = positiveInteger(params.get('hydrogenPage'));
    if (orderPage && orderPage > 1) context.orderPage = orderPage;
  }
  return context;
}

export function buildHydrogenDrillUrl(
  location: LocationParts,
  context: HydrogenDrillContext,
): string {
  const params = new URLSearchParams(location.search);
  for (const key of [
    'hydrogenLevel',
    'hydrogenYear',
    'hydrogenStation',
    'hydrogenStationName',
    'hydrogenCustomer',
    'hydrogenScope',
    'hydrogenStart',
    'hydrogenEnd',
    'hydrogenDate',
    'hydrogenPage',
  ]) {
    params.delete(key);
  }

  if (context.level !== 'overview') params.set('hydrogenLevel', context.level);
  if (context.year) params.set('hydrogenYear', String(context.year));
  if (context.level === 'station' && context.stationId !== undefined) {
    params.set('hydrogenStation', String(context.stationId));
    if (context.stationName) params.set('hydrogenStationName', context.stationName);
  }
  if (context.level === 'customer' && context.customerName) {
    params.set('hydrogenCustomer', context.customerName);
  }
  params.set('hydrogenScope', context.vehicleScope);
  if (context.startDate) params.set('hydrogenStart', context.startDate);
  if (context.endDate) params.set('hydrogenEnd', context.endDate);
  if (context.selectedDate) params.set('hydrogenDate', context.selectedDate);
  if (context.selectedDate && context.orderPage && context.orderPage > 1) {
    params.set('hydrogenPage', String(context.orderPage));
  }

  const query = params.toString();
  return `${location.pathname}${query ? `?${query}` : ''}${location.hash}`;
}